1. Field of the Invention
The present invention relates to a light emitting module and a method for manufacturing the light emitting module. Particularly, the present invention relates to: a light emitting module on which a high-luminance light emitting element is mounted; and a method for manufacturing the light emitting module.
2. Description of the Related Art
A semiconductor light emitting element represented by a light emitting diode (LED) has a long life and shows a high visibility. Accordingly, its use in traffic signals, lamps of automobiles, and the like, has been started. Moreover, use of an LED in lighting equipment is emerging.
When used in lighting equipment, a large number of LEDs are mounted in single lighting equipment, because merely a single LED cannot produce a sufficient brightness. However, an LED dissipates a large amount of heat during the light emission. Accordingly, when an LED is mounted on a mounting board made of a resin material that has an inferior heat-dissipating property, or when such individual LEDs are resin-packaged individually, heat is not desirably dissipated from the LED to the outside. Consequently, the performance of the LED is deteriorated soon.
Japanese Patent Application Publication No. 2006-100753 (JP-A 2006-100753) discloses a technology in which an LED is mounted on the upper surface of a metal substrate made of aluminum in order to desirably dissipating a heat generated from an LED to the outside. Particularly, with reference to FIG. 2 of JP-A 2006-100753, an upper surface of a metal substrate 11 is covered with an insulating resin 13, a conductive pattern 14 is formed on the upper surface of this insulating resin 13, and then a light emitting element 15 (LED) is mounted on the upper surface of the conductive pattern 14. With this configuration, the heat generated from the light emitting element 15 is dissipated outside via the conductive pattern 14, the insulating resin 13 and the metal substrate 11.
Nevertheless, in the technology described in JP-A 2006-100753, the layer of the insulating resin 13 covering the upper surface of the metal substrate 11 is exposed from the upper surface of the substrate. Meanwhile, when such an LED module is used, the upper surface of the substrate is irradiated with part of light emitted from the light emitting element 15. Accordingly, light emission from the light emitting element 15 over a long period causes discoloration and deterioration of the insulating resin 13, and consequently, the breakdown voltage of the insulating resin 13 is decreased.